Modafinil, C15H15NO2S, also known as 2-(benzhydrylsulfinyl)acetamide, or 2-[(diphenylmethyl)sulfinyl]acetamide, is a synthetic acetamide derivative with wake-promoting activity, the structure of which has been described in French Patent No. 78 05 510 and in U.S. Pat. No. 4,177,290 ('290), and which has been approved by the United States Food and Drug Administration for use in the treatment of excessive daytime sleepiness associated with narcolepsy. Modafinil has been tested for treatment of several behavioral conditions in combination with various agents including apomorphine, amphetamine, reserpine, oxotremorine, hypnotics, yohimbine, 5-hydroxytryptophan, and monoamine oxidase inhibitors, as described in the cited patents. A method of preparation of a racemic mixture is described in the '290 patent and a method of preparation of a levorotatory isomer is described in U.S. Pat. No. 4,927,855 (both incorporated herein by reference). The levorotatory isomer is reported to be useful for treatment of hypersomnia, depression, Alzheimer's disease and to have activity towards the symptoms of dementia and loss of memory, especially in the elderly. Modafinil has also been found to have application in the treatment of fatigue, and in particular the treatment of fatigue associated with multiple sclerosis, as well as sleepiness, Parkinson's disease, cerebral ischemia, stroke, sleep apneas, eating disorders, attention deficit hyperactivity disorder (described further below), for stimulation of appetite or weight gain, for promotion of wakefulness, or for improvement of cognitive dysfunction.
The primary pharmacological activity of modafinil is to promote wakefulness. Modafinil promotes wakefulness in rats (Touret et al., 1995; Edgar and Seidel, 1997), cats (Lin et al., 1992), canines (Shelton et al, 1995) and non-human primates (Hernant et al, 1991) as well as in models mimicking clinical situations, such as sleep apnea (English bulldog sleep disordered breathing model) (Panckeri et al, 1996) and narcolepsy (narcoleptic canine) (Shelton et al, 1995).
Modafinil has also been described as an agent with activity in the central nervous system, and as a useful agent in the treatment of Parkinson's disease (U.S. Pat. No. 5,180,745); in the protection of cerebral tissue from ischemia (U.S. Pat. No. 5,391,576); in the treatment of urinary and fecal incontinence (U.S. Pat. No. 5,401,776); and in the treatment of sleep apneas and disorders of central origin (U.S. Pat. No. 5,612,379). U.S. Pat. No. 5,618,845 describes modafinil preparations of a defined particle size less than about 200 microns. In addition, modafinil may be used in the treatment of eating disorders, or to promote weight gain or stimulate appetite in humans or animals (U.S. Provisional Patent Application No. 60/150,071, incorporated herein by reference), or in the treatment of attention deficit hyperactivity disorder (ADHD) as described in U.S. Pat. No. 6,346,548, or fatigue, especially fatigue associated with multiple sclerosis (U.S. Provisional Patent Application No. 60/149,612, incorporated herein by reference). ADHD is a chronic neuropsychiatric disorder in children that is characterized by developmentally inappropriate hyperactivity, impulsivity, and inattention. ADHD is estimated to affect 3%-5% of school-age children. The core ADHD symptoms in adults include a frequent and persistent pattern of inattention/distractibility and/or hyperactivity-impulsivity. The most common symptoms exhibited in ADHD adults are marked inattention, poor concentration, easy distractibility, day dreaming, forgetfulness, and a frequent shift in activities. ADHD adults also report marked impulsivity, intrusiveness, low frustration/stress tolerance, temper tantrums, irritability, and extreme impatience. Less commonly reported symptoms in adults include hyperactivity, which may be confined to fidgeting, or an inward feeling of jitteriness or restlessness. In addition to the core ADHD symptoms, adults with ADHD often exhibit associated clinical characteristics such as boredom, social inappropriateness, and chronic conflicts in social situations.
Modafinil was known in the art in the form of a therapeutic package, marketed under the name Provigil®. Provigil® is a pharmaceutical product sold by Cephalon, Inc. of West Chester, Pa. Provigil® is supplied as tablets containing 100 mg or 200 mg modafinil, with several excipients, including magnesium silicate and talc. In commercial use, modafinil-containing therapeutic packages are labeled for use in treating excessive daytime sleepiness associated with narcolepsy.